London Dermatologists Dr Monika Saha and Dr Anna Chapman report on an interesting case of a patient with pemphigus foliaceus (PF) and myasthenia gravis (MG) who was found to have Cushing syndrome due to an adrenal adenoma which had served to treat both autoimmune diseases.

A 44-year-old woman presented with a 4-year history of intermittent blisters and erosions affecting her trunk, face and limbs with no mucosal involvement. She was diagnosed with pemphigus foliaceus (PF). Three years prior to her diagnosis of PF, the patient had been diagnosed with myasthenia gravis (MG).

The patient was treated with prednisolone and then maintained on mycophenolate mofetil and prednisolone for several years.

Three years after the diagnosis of PF, it was noted that the patient had developed features of possible iatrogenic Cushing syndrome. After a further 4 years, the patient developed uncontrolled hypertension. For the first time, she was successfully weaned off all steroids and other immunosuppressant’s with no deterioration of her skin or neurological disease.

Seven months late the patient had a worsening of her symptoms and signs of Cushing syndrome. A cortisol-secreting adrenocortical tumour was identified as the likely diagnosis, confirmed as a left adrenal adenoma. The adenoma was surgically removed and the patient demonstrated a rapid and complete resolution of her cushingoid features with her weight and facial plethora improving and blood pressure normalizing. However, as her cushingoid features improved, her skin disease started to flare and by 3 months post surgery, the patient was developing new pemphigus lesions.

This case demonstrates an interesting phenomenon of endogenous suppression of two autoimmune diseases, PF and MG, into remission by an occult adrenal tumour and highlights the importance of careful clinical reviews and investigation of unexplained persistent symptoms in patients on long-term prednisolone and awareness of Cushing syndrome due to adrenal or pituitary pathology.

London Dermatologists Dr Monika Saha and Dr Anna Chapman see patients privately at The London Skin and Hair Clinic, a private medical dermatology clinic in central London.